Nice article--pretty much sums it up. With Hydrangeas that bloom on new wood, you will never have any blooming issues--with those new wood versions they always have great blooms here even though it routinely gets down to -20F to-25F. Annabelle, Incrediball, Limelight are a few(not a hydrangea expert, sure there are many more varieties) that will always bloom reliably with no fear of winter die back. You probably have some variety that blooms on old wood--depending on snow cover, temps, etc I guess could affect next years blooms.
My in laws have some old wood blooming hydrangeas(no idea what cultivar)--I've never seen them bloom once in 10+ years here in VT